Means for locating faults on alternating-current circuits.



K. H. BAUSMAN. MEANS FOR LOCAING FAULTS 0N ALTERNTING CURRENT CIRCUITS. l

APPuArm man Has. 1. um.

Patented web.v i2, uns.

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KARL H. BAUSMAN, 0F DAYTON, OHIO.

MEANS FOR ILO(lA'ILIlI'lIi FAULTS ON ALTERNATING-CURRENT CIRCUITS.

Specicaton of Letters Patent.

retreated renie, raie.

Application led February 7, 1917. Serial No. 147,073.

To all whom it may concern.

Be it known that I, KARL H. BAUsMAN, citizen of the United States, residing at Dayton, in the county of Montgomery and State of Ohio, have invented certain new and useful Improvements in Means for Locating Faults on Alternating-Current Circuits; and I do declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same, reference being had to the accompanying drawings, and to the letters and figures of reference which form a -part of this specilication.

This invention relates to an improved method for locating trouble such as accidental grounds or short circuits in alternating current, light and powersystems, and consists of a portable equipment and its use such as will be hereinafter described.

The means heretofore employedso far as I am aware, for locating grounds, short circuits, etc., on electric wiring is a long and tedious process resulting in many instances in having to cut the wiring Vat numerous places ;in an effort to locate the trouble. This ofcourse is an expensive method, especially when large cables and conduit wiring are to be dealt with in locating and repairing wire trouble. It is therefore the object of the present invention to provide means whereby the time and labor consumed in locating trouble are greatly reduced and the expense attending the cutting of wires, the taking up of structures, such as lloors, walls, ceilings, etc., of buildings is avoided.

rlhe present means is diagrammatically illustrated in the accompanying drawing, in which two examples of wire trouble are illustrated, to-wit, that caused by accidental short circuiting, and that due to the accidental grounding of a circuit. The means consists of a coil, otherwise termed a detector or exploring coil, which is inclosed in casing l; a high resistance telephone receiver' 2 connected to said exploring coil; and a reactance coil 3, the latter being also inclosed within a portable casing. The exploring coil consists primarily of a laminated iron core on which is wound a coil consisting of a great many turns of iine copper wire, the terminals of which are connected to binding posts. The said exploring coil may be varied 1n the matter of the winding or size of the marked thereon, Y

coil. The exploring coils may be of various sizes depending upon the work, a smaller coil being used for detecting more severe grounds and a longer coil when greater sensitiveness is necessary. The receiver 2 is of a very sensitive type, for example the kind used in wireless telegraph stations. The reactance coil consists of a number of turns of copper wire wound on a laminatediron core, with numerous taps brought out to the binding posts. The purpose of the reactance coil is to introduce reactance into the circuit under scrutiny, thereby changing the wave form and amplitude of the current so as to give an amplified tone or hum in the receiver different from the tone or hum of the ordinary lighting and power circuit; and also to limit the current. It is by means of this audible difference in the tone thus produced in the case of trouble that the trouble is located. In other words, the application of the reactance coil to a trouble circuit produces a tone in the receiver which is different and distinct from .the tone or hum of a circuit in which the reactance coil is not connected.

Describing more particularly the use of my improved trouble locating means: In case a ground occurs on a circuit the reactance coil is connected in series with the grounded line by using a tap which will limit the current to, say, 3 or 4 amperes or even less. The operator by holding the exploring coil near the wire and parallel to it will hear a distinct hum in the receiver if there is any current flowing through the wire as the current in the line will induce a current in the exploring coil. The hum will be dierent in tone from that given by the current not affected by the reactance coil. He then proceeds to follow the circuit with the exploring coil, the direction of the wires coinciding with the direction of the coil when the maximum hum is heard in the receiver.

s soon as the exploring coil passes over the point of trouble, the hum ceases unless the current is flowing' through the gas or water pipes extending in some direction other than that of the wiring. This is ascertained by following the pipe to the remainder of the piping system in the building. In the case of trouble due to a short circuit, the reactance coil is connected in the circuit to limit the current, and the same procedure is followed as in the case of les yisbeing worked upon a ground. This connection may be conveniently made at the fuse blocks. Vith a little experience a person becomes Vaccustomed to the use of the instrument and Vcan readily locate trouble such as that due to grounds or short circuit, etc., onv practically any kind of wiring. By merely holding the exploring coil in proximity to or against any conductor, the operator is enabled to instantly detect whether current is. flowing through the conductor or not. The apparatus may be used to trace or locate wiring, gasvor water pipes, conduits, etc.; in fact most anything that carries current. Referring to the annexed diagram the proportional amount of reactance coil is indicated by the several figures shown thereon from 0 to 100. By varying the reactance of the reactance coil the circuit that may from any other circuit in the tone derived therefrom. In addition to amplifying the sound given 0H by the receiver', the variablereactance changes the wave form of the current, thereby giving to the receiver-vibra-V tions a tone entirely-different from that produced by energy delivered to any point of current consumption. Therefore it is unnecessary to interrupt the circuit carrying energy to electrical devices when locating a ground on this circuit. The reactance coil has a laminated circular iron core having a cross-sectionalarea ofA 2 sq. in. vThe winding consists of L00 turns of No. 15 single cotton-covered wire arranged in two sections of 200 turns each. Taps are brought out at the LlOth, 80th, 100th, 120th and 160th turn of each section.

I will now give a specific instance of locating a ground and a short circuit. In the diagram, A B C represent a three-wire secondary, covering a district, say, of about two thousand feet. G represents a permanent ground wire connected to the neutralv wire B near the transformer. Assuming that an accidental ground has occurredsolnewhere on the secondary system illustrated at X on the diagram, such a condition puts an excessive voltage between the house wiring. and the gas or water pipes, and it is the practice lof all central stations to clear up trou Copias ci this patent may be obtained for in Vthe reactanccV be distinguished Vapparadons five-cents each,

Washington, '.D. G.

ble such as thiscas soon as possible. The procedure with my invention is as follows:

The` variable reactance coil is connected in series with the permanent ground wire G, using a tap thatwilllimitthe 1current to 3 or 4: amperes or less. The loperatorl adjusts the receiver to the ear and secondary A B C at a point near the transformer, holding` the exploring coil parallel to the wires. He immediately locates the hum produced bythe current flowing in the defective circuit and follows this hum, walking under the wires until it becomes inaudible. I-Ie then holds the exploring coil parallel to the nearest service wires until he again picks up'the hum and follows this service into the house or building to the point where the wire is touching thepipe. It should be borne in mind that the apparatus is so sensitive that a trainedear can detect the ground current of only a few amperes when the exploring coil is held as far as l() feet from the conductor, thus it will be seenl that the is sensitive enough for detecting grounds on most lines strung overhead. with the operator standing on the ground. In case a short circuit occurs on'the wiring in a house or building, the reactance coil is connected in series with the defective circuit,

usually by replacing one fuse plug with an attachment plug and cord connected to the said coil, using va tap in thereactance coi that willlimit he current to a few amperes. The same procedure isfollowed with the exploring coil and receiver, following the wiring through the house Vor building directed by the h um until this hum ceases, at which point the shortvcircuit existsf I-Iaving described my invention, I claim: The method of testing a conductor network for faults which consists in applying a source of varying current tothe net-work,

connecting an inductance insaid net-work so as to bev included in the probable. path of fault current and thereby causing a change in wave form in said KARL nl. sansa/LAN.

by adahjessingl the Commissioner o! latente,

stands Vunder the K v fault current, and then l exploring the net-workby an exploring coil.V

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